1. Field of the Invention
The present invention relates generally to a method of detecting an ink residual quantity in an ink jet printer and, more particularly, to a method of detecting an ink residual quantity in an ink jet printer having a reciprocating carriage mounted with an ink jet head and an ink tank.
2. Related Background Art
There are a variety of methods in ink jet printers. In any method, generally, a residual quantity of the ink within an ink tank is detected, and the user is warned of an ink exhaustion.
The above-described method of detecting an ink residual quantity includes those of detecting an electric resistance value of the ink and optically detecting an ink liquid level. Herein, there arise the following problems inherent in the ink jet printer of such a type that a carriage mounted with the ink tank is reciprocated together with an ink jet head. Ink oscillations are caused because of the acceleration acting on the ink tank mounted on the carriage during bilateral turnabouts of the carriage. In this state, the ink residual quantity can not be accurately detected by any method.
Hence, this type of ink jet printer has hitherto involved the step of detecting the ink residual quantity by setting the carriage in a home position after performing one-page printing or detecting the ink residual quantity by stopping the carriage similarly in the home position for a short period of time after performing the one-page printing.
Further, some printers incorporate the liquid level oscillation preventive mechanism having a complicated structure so as not to cause the oscillations of the liquid level to prevent a sway of the ink.
The foregoing method of detecting the ink residual quantity per page presents such a big problem that the ink is consumed up during printing when the page size is as large as A1 or A2.
In addition, the method of detecting the ink residual quantity by stopping the carriage for the short time per line causes a problem wherein an accumulating total of the stop time exerts an influence on a printing efficiency as a loss of printing speed if the number of printing lines is large.